Black Friday Shopping

Nan Dong
12/2/2015

Constraints

Problem: There are too many attractive deals on Black Friday, I need to use LP to help me figure out which items I should purchase.

Constraints are:

  1. MONEY!

  2. Some of the items are gifts,which means I have to purchase.

Shopping List:

\( i \) Item Price Value
1 Iwatch 349 10
2 Wallet 349 9
3 Withings Activite Pop smartwatch 99.99 10
4 Lululemon yoga pants 108 9
5 Swaroski earrings 30 10
6 $30 gift card 30 9
7 Under Armour Coat 59.99 7
8 Lindl Chocolate 25 10
9 Sumsung wireless headphone 29.99 5

Shopping list(cont.)

\( i \) Item Price Value
10 Tory Burch handbag 223 3
11 Nike shoes 49.99 4
12 Ugg boots 80 5
13 Coach wallet 20 8
14 Crabtree hand lotion set 30 6
15 Iphone6 case 9.99 3
16 Lululemon yoga mat 78 2
17 scarf 40 8
18 Earpuff 30 8
19 Donation for Kids 30 10
20 Sephora giftcard $25 20 4

Assign Variables & Objective functions

\[ \tiny Let\, x_i =\begin{cases} 1 & if\,I\,should\,purchase\, item\, i\,, \\ 0 & otherwise \end{cases} \]

\[ Maximize\sum_{i=1}^{20} X_i*Value_i \]

Constraints: \[ let\,Y=\sum_{i=1}^{20} X_i*price_i<=700 \] X1+X2=1; X3+X4=1; X5+X6=1; X8=1; X20=1

Solution:(Lindo)

OBJECTIVE FUNCTION VALUE

    1)      87.00000

Translated Results:

Items should buy Items should not buy
Iwatch Wallet
Withings Activite Pop smartwatch Lululemon yoga pants
Swaroski earrings $30 gift card
Lindl Chocolate Under Armour Coat
Coach wallet Sumsung wireless headphone
Crabtree hand lotion set Tory Burch handbag
Iphone6 case Nike shoes
scarf Ugg boots
Earpuff Lululemon yoga mat
Donation for Kids Wallet
Sephora giftcard $25 Lululemon yoga pants

Suggestions for online shopping:

*Find Deals or Coupon: dealmoon,google

*Buy discounted giftcards (ecode): giftcard.com,cardpool.com

*Ebate.com

For example: you want to buy 100 dollor item on Macys.com

*go to cardpool.com spent $90 on $100 giftcard

*open macys.com through Ebates, get $6 cashback.

100-10-6=$84